Variable compression ratio engines allow achieving high compression ratios, typically by means of an additional adjustable piston opposing the primary piston.
An example of such configuration is shown in a U.S. Pat. No. 6,708,655, which describes an internal combustion engine, comprising a combustion cylinder, a cylinder head at an end of the combustion cylinder and a primary piston reciprocally disposed within the combustion cylinder. The cylinder head includes a secondary cylinder and a secondary piston reciprocally disposed within the secondary cylinder. An actuator is coupled with the secondary piston for controlling the position of the secondary piston dependent upon the position of the primary piston, and a communication port establishes fluid flow communication between the combustion cylinder and the secondary cylinder. The actuator can be hydraulic or a cam actuator. The construction of the device is relatively complex.
The aim of the present invention is to provide a compensating arrangement for a variable compression ratio engine which has a simple construction and high efficiency.